This invention relates to a method of and apparatus for the continuous production of profile members, hollow bodies, etc., from a plurality of metal strips, especially steel strips or bands, which are of constant thickness and are of straight and/or profiled cross-section, by heating selected areas of the metal strips and joining the strips or bands by press-welding the related areas together.
Tubes of constant wall thickness have been produced from a continuous band which is heated to a temperature of about 1250.degree. to 1300.degree. C., is shaped between rotating rollers, is connected by pressing together the opposite edges of the band and is then grooved while in a heated state to its final diameter. According to German DE-PS No. 1,452,500 the method of producing thin-walled tubes by means of press-welding may be further improved if, in addition to the application of oxygen to the band edges, the band edges are locally heated by high-frequency induction heating.
German DE-PS No. 970,422 discloses the practice of forming closed and open profile members from two or more parts, either preformed or of straight profile, by butt-welding the edges to be connected. German DE-AS No. 1,097,391 discloses a method for the continuous production of profile members from a plurality of part-profile members. The individual part-profile members are first formed after which one of the part-profile members is twisted into position such that the free edges of all of the part-profile members are properly located with respect to each other for the formation of the hollow profile member by subsequent butt-welding of the free edges.
German DE-AS No. 1,085,980 discloses the conductive welding of the edges of a profile strip with a band-like surface portion of a workpiece having an extended upper surface. Separate parts are brought together in a continuous operation and are welded to form the desired profile member, the cross-section, i.e., thickness, of the walls of the finished product remaining unaltered, i.e., constant. Irregularities produced by welding are removed by further operations, such as a grooving process to bring thickened portions to their initial thickness.